When we think of “first responders,” our thoughts turn normally to police officers, firefighters and emergency medical personnel.

The tragedy that erupted this week in Parkland, Fla., however, has offered a grim new reality. First responders quite often — too damn often! — are people who aren’t trained to fulfill that role. School teachers have taken on that role whenever madmen open fire in classrooms, or in hallways.

A beloved football coach gave his life on Valentine’s Day when he shielded students from the shooter who opened fire at the Parkland high school. He was one of three educators who died while performing acts of heroism.

And yet, they were among many teachers who answered the call when the shooting began.

This is not what educators sign on to do when they take these jobs. They are committed to teaching young people, educating them and preparing them for their journey into adulthood.

The Parkland tragedy, along with the Sandy Hook tragedy in 2012, or the Columbine tragedy in 1999 remind us that danger lurks in places where — in a better world — we shouldn’t expect to find it.

I’ve often expressed my admiration for the first responders, the folks trained to do those tasks. I also have offered by salute to educators committed to shaping young people’s lives and the commitment they demonstrate each day in the classroom.

We must rue the era that has dawned on us that teachers, too, are able to perform acts of heroism. It is, I fear, a tragic sign of our time.